Question 1

You are hired to work in a laboratory to measure the rate of human muscle contraction. Which of the following might decrease in quantity in muscle fibers undergoing contractions?

Accepted Answer

A)   ATP
B)   Carbon dioxide
C)   Water
D)   Lactate
E)   Na+F) C) and D)
G) D) and E)

Question 2

Which of the following events occurs during the lag phase of a muscle twitch?

Accepted Answer

A)   Muscle fibers shorten.
B)   Cross-bridges form, move, release, and reform many times.
C)   The action potential is propagated from presynaptic to postsynaptic membrane.
D)   Ca2+ are pumped back into the sarcoplasmic reticulum.
E)   All of these events occur in the lag phase.F) B) and C)
G) A) and C)

Question 3

Which of the following is NOT a known effect of illegal use of anabolic steroids in large dosages?

Accepted Answer

A)   Increased muscle size
B)   Kidney damage
C)   Diminished testosterone secretion
D)   Increased cardiovascular fitness
E)   SterilityF) C) and E)
G) None of the above

Question 4

What is a cross-bridge?

Accepted Answer

A)   A protein found along the groove of the F-actin double helix
B)   A T tubule and two adjacent terminal cisternae
C)   The combination of myosin heads with active sites on actin molecules
D)   The movement of myosin head while attached to actin myofilament
E)   After exercise, the O2 taken in that exceeds the O2 required for resting metabolismF) A) and D)
G) A) and C)

Question 5

The region of the sarcomere that contains both actin and myosin myofilaments is called the

Accepted Answer

A)   I band.
B)   A band.
C)   Z disk.
D)   H zone.
E)   M line.F) A) and B)
G) All of the above

Question 6

A lack of mitochondria within skeletal muscle fibers would impair which ATP-yielding chemical process?

Accepted Answer

A)   Anaerobic respiration
B)   Aerobic respiration
C)   Both anaerobic respiration and aerobic respiration are correct.D) None of the above
E) All of the above

Question 7

During resting conditions, ________ is synthesized to store energy.

Accepted Answer

A)   Ca2+
B)   creatine phosphate
C)   creatinine
D)   lactate
E)   pyruvateF) A) and E)
G) B) and E)

Question 8

The sarcoplasmic reticulum

Accepted Answer

A)   stores Ca2+.
B)   shortens during muscle contraction.
C)   transmits nerve impulses to the myofibrils.
D)   connects adjacent sarcomeres.
E)   covers the muscle fiber.F) B) and E)
G) B) and C)

Question 9

Heather is watching a movie. Which type of chemical pathway does her muscles depend on at this time?

Accepted Answer

A)   Anaerobic respiration
B)   Aerobic respiration
C)   Both anaerobic respiration and aerobic respiration are correct.D) A) and B)
E) A) and C)

Question 10

Which of the following correctly describes myoglobin's special function in muscle tissue?

Accepted Answer

A)   Breaks down glycogen
B)   Synthesizes ATP
C)   Acts as a reservoir for O2
D)   Produces action potentials
E)   Stores glucoseF) None of the above
G) All of the above

Question 11

Diseases that affect the ability of skeletal muscle to contract are considered life threatening because

Accepted Answer

A)   the movement of blood through the blood vessels of the body depends solely on skeletal muscle contractions.
B)   respiratory movements depend on skeletal muscle contractions.
C)   movement of food through the digestive tract depends on skeletal muscle contractions.
D)   All of the choices are correct.E) B) and D)
F) B) and C)

Question 12

Which of the following events occurs on the postsynaptic membrane?

Accepted Answer

A)   Acetylcholine production
B)   Rapid degradation of acetylcholine
C)   Release of neurotransmitter
D)   Neurotransmitter combines with a receptor molecule
E)   Release of Ca2+F) C) and D)
G) B) and C)

Question 13

The diffusion of Ca2+ into a smooth muscle cell does not depolarize the membrane so no action potential occurs.

Accepted Answer

A) True 
 B)False

Question 14

Smooth muscle

Accepted Answer

A)   responds in an all-or-none fashion.
B)   depolarizes when both Na+ and Ca2+ diffuse into the cell.
C)   has fast waves of depolarization.
D)   has fast waves of repolarization.
E)   has a resting membrane potential that is more negative than skeletal muscle fibers.F) B) and C)
G) C) and E)

Question 15

A by-product of anaerobic respiration in muscle fibers is

Accepted Answer

A)   uric acid.
B)   hydrochloric acid.
C)   lactate.
D)   oxygen.
E)   pyruvate.F) A) and B)
G) A) and C)

Question 16

An action potential

Accepted Answer

A)   occurs when the local potential reaches threshold level.
B)   is not propagated.
C)   has no repolarization phase.
D)   is an example of negative feedback.
E)   can be of varying strengths depending on strength of the stimulus.F) None of the above
G) B) and E)

Question 17

Which of the following would occur as a result of a single muscle contraction?

Accepted Answer

A)   Tetanus
B)   Tone
C)   Treppe
D)   Twitch
E)   ParalysisF) A) and B)
G) A) and C)

Question 18

A myofilament is the

Accepted Answer

A)   plasma membrane of a muscle fiber.
B)   cytoplasm of a muscle fiber.
C)   structural and functional unit of the skeletal muscle fiber.
D)   contractile thread that extends the length of the muscle fiber.
E)   protein strand composed of actin or myosin.F) C) and E)
G) C) and D)

Question 19

What are caveolae?

Accepted Answer

A)   Ion channels that allow for rapidly developing action potentials
B)   Shallow invaginations of plasma membrane
C)   Structures that allow for relatively constant tension maintained for a period of time
D)   Parts of the intracellular cytoskeleton
E)   Enzymes that removes phosphate from myosinF) B) and D)
G) B) and E)

Question 20

Which of the following statements best distinguishes between tetanus and treppe?

Accepted Answer

A)   Tetanus is due to repeated stimulation of the muscle; treppe is the result of a single long stimulation of the muscle.
B)   Tetanus occurs when stimulation of muscle occurs frequently with little to no relaxation between stimuli; treppe occurs when stimulation of muscle occurs frequently, but complete relaxation occurs between stimuli.
C)   Tetanus only occurs in laboratory settings, but treppe occurs all the time in normal muscle activity.
D)   Tetanus involves increasing the number of motor units stimulated simultaneously; whereas, treppe involves the repeated stimulation of a single muscle fiber.E) C) and D)
F) B) and D)

Exam 9: Muscular System: Histology and Physiology

Which of the following would occur as a result of a single muscle contraction?

Correct AnswerverifiedShow Answer

Which of the following statements best distinguishes between tetanus and treppe?

Correct AnswerverifiedShow Answer

The sarcoplasmic reticulum

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Which of the following correctly describes myoglobin's special function in muscle tissue?

Correct AnswerverifiedShow Answer

A lack of mitochondria within skeletal muscle fibers would impair which ATP-yielding chemical process?

Correct AnswerverifiedShow Answer

A by-product of anaerobic respiration in muscle fibers is

Correct AnswerverifiedShow Answer

Which of the following events occurs during the lag phase of a muscle twitch?

Correct AnswerverifiedShow Answer

The diffusion of Ca2+ into a smooth muscle cell does not depolarize the membrane so no action potential occurs.

Correct AnswerverifiedShow Answer

During resting conditions, ________ is synthesized to store energy.

Correct AnswerverifiedShow Answer

What are caveolae?

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Heather is watching a movie. Which type of chemical pathway does her muscles depend on at this time?

Correct AnswerverifiedShow Answer

A myofilament is the

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What is a cross-bridge?

Correct AnswerverifiedShow Answer

You are hired to work in a laboratory to measure the rate of human muscle contraction. Which of the following might decrease in quantity in muscle fibers undergoing contractions?

Correct AnswerverifiedShow Answer

Diseases that affect the ability of skeletal muscle to contract are considered life threatening because

Correct AnswerverifiedShow Answer

Which of the following events occurs on the postsynaptic membrane?

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Smooth muscle

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Which of the following is NOT a known effect of illegal use of anabolic steroids in large dosages?

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The region of the sarcomere that contains both actin and myosin myofilaments is called the

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An action potential

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The diffusion of Ca²⁺ into a smooth muscle cell does not depolarize the membrane so no action potential occurs.

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